1. Field of the Invention
The present invention relates to a sensing apparatus and, more particularly, to such a sensing apparatus which is capable of monitoring predetermined conditions to be sensed in a wide variety of environments with a stability and immunity from error not heretofore achieved in the art.
2. Description of the Prior Art
With technological advance comes the accompanying necessity for maintaining control over an increasing number and variety of subsystems. The necessity for this capability becomes increasingly important with the prolixity of the subsystems involved. Similarly, this necessity is increasingly more important with the sensitivity of the subsystems and is dependent, as well, upon the ranges of operation required and the tolerances which may be acceptable. Thus, for example, if the particular device under consideration is an automotive vehicle, the number of subsystems and the ranges and tolerances of acceptable operation may be relatively benign. Alternatively, if the particular device is a jet aircraft or a space vehicle, the numbers of subsystems and the ranges and tolerances of acceptable operation may be significantly more critical and unforgiving. Accordingly, the use of accurate and reliable sensors for monitoring such subsystems has become of critical importance in the satisfactory operation of an ever increasing number and variety of devices upon which society depends.
A wide variety of types of sensors have conventionally been known including those which are purely mechanical, as well as those which are electromechanical, electronic and electrochemical. There are also those which have a redundant capability. Such conventional sensors have been plagued by a number of characteristic problems which severely hamper their reliability in use. Among these is a variety of strain gauges, or pressure transducers, which have been employed in the measurement of pressure. These have included gauges which can be classified generally as expansible metallic-element gauges and electrical pressure transducers. Pressure transducers may be subclassified as including resistive pressure transducers, strain gauge pressure transducers, magnetic pressure. transducers, crystal pressure transducers and capacitive pressure transducers. These can further be subcategorized, but to varying degrees all such conventional devices suffer from certain deficiencies including instability due to physical shock, attitudinal variation, thermal deviation and the like. These are all conditions which are experienced in such critical operative environments as aircraft and space craft and in which the margin for error, both in terms of time and degree, is minuscule.
Therefore, it has long been known that it would be desirable to have a sensing apparatus which is particularly well suited to use as a universally adaptable measuring apparatus for a wide variety of operative environments; which is readily suited to usage in a plurality of subsystems in a given operational environment so as to establish a uniformly reliable and comparable source of information for the specific operational environment; which possesses a stability and immunity to thermal deviation not heretofore achieved in the art; which is uniquely well suited to providing readily usable data to conventional monitoring systems as well as more nonconventional monitoring systems; which is of minimal cost and weight while being precisely accurate in a wide variety of operative environments; and which is otherwise entirely successful in achieving its operational objectives.